This invention relates to a cabling assembly for improved data transmission, and more particularly to a cable assembly with molded strain relief that is suitable for use in high-speed data communication applications and a method for making the same.
The purpose of network and telecommunication cables is to carry data or signals from one device to another. As telecommunication and related electronic networks and systems advance to meet the ever-increasing needs of the modem world, it has become increasingly important to improve the speed, quality and integrity of the data or signals being transmitted. This is particularly important for higher-speed applications, where resulting losses and distortions can be magnified.
One method of transmitting data and other signals is by using an individually twisted pair of electrical wires, where each wire has been coated with a plastic or thermoset insulating material. After the wires have been twisted together into cable pairs, various methods known in the art may be employed to arrange and configure the twisted wire pairs into high-performance transmission cable arrangements. Once twisted pairs are configured into a xe2x80x9ccore,xe2x80x9d a plastic or thermoset material jacket is typically extruded over the twisted wire pairs to maintain the configuration and to function as a protective layer. When more than one twisted pair group is bundled together, the combination is referred to as a multi-pair cable. Such multi-pair twisted cabling is commonly utilized in connection with local area network (LAN) applications.
In the past, patch cord cable assemblies for data networking systems, such as those used in company LANs, have been considered to be low cost, somewhat dispensable items. Recently, as required transmission speeds have increased, it has been found that the patch cord cable assemblies can drastically impact the data throughput of the systems. Practice has shown that a significant portion of the data or signal loss and/or distortion occurs at the areas with the highest stress, due to flexing, tension or torsional twisting, on the cable. A common problem is found in LANs where a four-pair cable connects to and exits a modular plug, the critical area being where the pairs are altered for termination and connection purposes. To address some of the associated problems, the network industry has adopted certain conventions and standards. For instance, to comply with ANSI/TIA/EIA 568A-1,a minimum bend radius of 25.4 mm (1.0 in.), or about four times the overall cable diameter, should be maintained.
Moreover, when in service, flexible cables are often routed in a variety of paths. The associated flexing, twisting, bending, and pulling of the cable is consequently transferred to the wires or wire pairs contained therein. Such stresses can lead to misalignment of the wires and can create a number of commonly recognized data transmission signal losses and distortions, such as delay skew.
One method to minimize the stress associated with such twisted pair cabling connections is to incorporate some form of stress relief into the cable assembly. However, traditional stress relief members, often act only as a cover or protective plate and do not function as a solid unit with the cable, hence, an unacceptable level of stress can still be imparted on the assembly. Therefore, a need exists for improved high-end cabling that can be adapted to a number of geometric configurations; can be readily implemented and installed; and can eliminate or minimize losses and distortion associated with the stresses directed upon the cable assembly.
Accordingly, it is a primary object of the present invention to provide an improved cable assembly that overcomes the shortcomings and limitations associated with prior paired electrical wires and cabling techniques.
It is another object of the present invention to provide a cable assembly with improved structural characteristics, particularly in the connection between a modular plug and associated data transmission cable so as to minimize data losses and distortion.
It is still another object of the present invention to provide a cable assembly that reduces the amount of stress between a modular plug and an associated data transmission cable having one or more twisted ware pairs.
It is a further object of the present invention to provide a high-end cable assembly suitable for use in high-speed data transmission applications with improved electrical and mechanical properties when compared to similar assemblies that employ conventional techniques.
It is yet a further object of the present invention to provide a cable assembly that reduces the amount of time associated with the manufacturer""s assembly and subsequent installation.
It is still a further object of the present invention to provide an improved cable assembly that can be easily adapted to function with cables having a variety of geometric cross sectional configurations.
Other and further objects, advantages and novel features of the invention will become apparent from the following detailed description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, several embodiments of the present invention are disclosed.
To achieve the foregoing and other objects, and in accordance with one aspect of the present invention, a cable assembly is disclosed which includes a cable, a modular plug, and a molded stress relief body. The cable includes at least one twisted wire pair of a given length and at least one outer jacket that surrounds a portion of the length of the twisted wire pair, wherein each individual wire of the twisted wire pair is comprised of a conductor wire and an outer insulator. The modular plug includes an uppermost surface and a receiving cavity to establish an electrical connection with the cable. A molded stress relief body is used to cover at least a portion of the cable and the modular plug. To reduce the amount of stress and strain encountered by and between the modular plug and the cable, the molded stress relief body is molded about, or bonded to, at least a portion of the twisted wire pair that is not surrounded by the outer jacket of the cable. Hence, the molded stress relief body provides a connection between the cable and modular plug and is firmly attached to the twisted pair so as to effectively xe2x80x9cfreezexe2x80x9d the twisted wire pair, or pairs, in place to improve the connection and durability of the assembly.